IN TROD UCTION. 



No. I is the thinnest, and is what ought to be used. They vary in thickness from -004 to -008 

 inch in thickness. 



(a) \ oz. extra thin f inch circles, or No. I. 



(b~) \ oz. extra thin i inch circles, or No. i. 



(c) % oz. extra thin i inch circles, or No. i. 



These covers ought to be arranged, according to their size and thickness, in a small box 

 divided into compartments by means of small pieces of pasteboard. This the student can 

 easily make for himself. 



9. A pine-wood box, or cabinet, provided with trays, so that the specimens may lie on the 

 flat. The trays ought to be made both for large and small slides, and the cabinet ought to 

 contain at least six dozen slides. Each student in the class of practical physiology mounts 

 over one hundred slides in a session. 



10. Reagents. Each student ought to be provided with a small wooden framework for 

 holding bottles, containing the solutions in common use. 



It is not of much importance what kind of bottle is employed. One-ounce bottles with 

 moderately wide mouths, and fitted with a glass rod passing through the cork, answer ad- 

 mirably. The solutions most commonly employed are : 



1. | per cent, salt solution (p. xxx). 



2. Dilute Acetic Acid, i part to 10 of water. 



3. Solution of Picrocarmine (p. xliii). 



4. Solution of ordinary Carmine (p. xliii). 



5. Solution of Logwood ($. xlii). 



6. Clove oil. It is advantageous to use a camel-hair 

 or sable brush fixed to the end of a piece of wood thrust 

 through the cork. 



7. Dammar Mounting Fluid (p. xlviii). 



8. Glycerine. 



9. Farrants Sohition (p. xlviii). 



The other solutions are supplied as they are required. 

 Ranvier uses a very convenient arrangement for 

 holding the reagent bottles (fig. 3). It consists of a 

 circular glass vessel, about four inches in diameter and 

 two inches deep. Into its mouth a perforated plate of 

 cork is fitted, and in this cork small ' drop bottles ' are 

 fixed, and the whole is covered with a glass shade to keep out dust. Anyone can easily make 

 such an arrangement for himself. 



10. Narrow strips of blotting paper, which ought to lie in a small tray attached to the 

 stand containing the reagents. They are of use to soak up surplus fluid, and also serve 

 as a white background, when such is required, as in teasing certain coloured preparations. 



Watch-glasses and small glass capsules are required, and the student will find the instru- 

 ments of his dissecting case very useful. Glass pipettes are occasionally required to remove 

 fluid. They are easily made by heating a narrow glass tube in a gas flame, and then drawing 

 it out. 



Fig. 3. RANVIER'S ARRANGEMENT FOR 

 HOLDING DROP-BOTTLES WITH RE- 

 AGENTS. 



